Means for the grading of powdered material by elutriation or hydraulic classification



V Dec. 14 1926. 1,610,725 r 4 L. ANDREW MEANS FOR THE GRADING OF POWDER'ED MAT IAL BY EIJUTRIATION OR HYDRAULIC CLASSIFICATION I Filed March 1'7 1925 netted a; 14 1192c. J,

*i'TEn STATES LEONARD Annnnws, or wns-rirrnsrnn, ENGLAND.

MEANS FOR THE GRADING OF POVVZDERED MATERIAL BY ELUTRIATION OB fi YDm'fl'LIG l CLASSIFICATION.

- Application filed March 17, 1925,'Seria1 No.

For use in the arts and manufactures, it is often necessary to provide powdered inaterial-thatis of a very/high degree of fineness and is homogeneousin character.

a As instances ofisuchmateriaL-there may be mentioned pigments, abrasives, pottery slips, rullers earth, fillers for asphalt in road making and so forth.

The present invention has for its object to enable the grading of finely ground material in a wet condition, to be efiected in such, a. way that material of the required degree of fineness and homogeneity can be obtained in a more rapid, advantageous and is economical manner than heretofore. V

F or this purpose according thereto, finely ground wet material (hereinafter called for brevity raw material) is delivered from a feed hopper into a stream of water that is '20 supplied through a valve controlled supply ceptacle and fine materirjg, mixed with water and with more or less aterial of an intermediate degree of fineness (hereinafter called v for distinction semi-coarse material), being delivered into the lower end 01E a chamber (hereinafter called the siphon chamber) wherein Water carrying fine material'rises and overflows into another or settling re- 'cepta'cle, whilst semi-coarse material will fall to the bottom of the siphon chambers. The water flowing ofi with the coarse material is caused to rise into a chamber (here inafter called the overflow chamber) whence 40 it flows into a float chamber that is in communication with the vortex chamber or channel or Y siph'on chamber. The float chamber contains a floatadaptedfiyithe varying level 1 'ofwater in such chamber, to cause the interv I 5 mittent opening and'closing of the valvein the pipe for delivering water under pressure,

together with raw material, into the vortex v chamber or channel (hereinafter called the -11.- vortex chamber). The feed hopper maybe provided with al sieve of suitable'mesh for arresting ground'material of toolarge a size to be advantageously'dealt with.

Means maybe provided for controlling the rate of flowof waterfrom the'siphom thecollecting chamber h. The vertical pipe chamber to the settling chamber. Means 16,197, and in Great Britain iirmn ae; 1924.

hopper and to break up fiocculent material therein. Also, means may be provided for causing water to fiow upward in an intermittent manner through the collecting re ceptacle, in order to remove fine material from the coarse material therein. Associated with the latter chambermay be provided a final discharge chamberwfor coarse*material, and means for automatically opening and closing the latter chamber.

Apparatus suitable for efiecting the grad ing of finely divided wet material according to the invention, can" be constructed in va rious forms, one example being illustrated in Fig. 1 of the accompanying drawings which is' a semi-diagrammatic part. sectional view ofthe general arrangement. Figs. 2 and 3 are views of supplementary means hereinafter referred to.

As here shown, the vortex chamber is formed-between inner and outer Walls a, b so asto form an endless channel of more or less annular shape. Arranged between a valvecontrolled high pressure water supply pipe I: and the lower end portion of the vortex chamber are two ejector nozzles d, 0 arranged in series and the forward of which (Z is arranged tangentially to the channel so as to cause water to circulate aroundvthe same at-a high speed. At one side ot the vortex channel and at the outer side thereof, is an upwardly inclined outlet fTeading to the upper, concave end 9 of a coarse material collecting chamber h the lower portion of which is ofconical shape having an outlet 71 at the bottom forcoarse materials and. a laterally arranged vertical outlet 7' at the top communicating through a vertical pipe 7 with anoverflowphamber m, that may beof inverted conical 'sh ape, and, serving for the passage of water with fine m'aterial from is provided, intermediate of its length,

with an expansion chamber n of double conical shape to facilitate separation of any semi-coarse material present, from the fine material flowing with the water to the over- 6. flow chamber m. The latter chamber, with a lower tubular extension m thereof, may bemade vertically adjustable in the said vertical pipe, as by a rack and pinion m for the purpose hereinbefore referred to. At

another portion of. the annular vortex channel is an outlet passage 0 through which water carrying fine and semi-coarse material can esca e from the said channel. The outlet passage 0 is connected by a bent pipe to a nozzle 9 arranged to direct the escaping water laterally and at relatively high speed- 1111130. the lower end of a conicalsiphon cham-,

ber r of large capacity arranged above the vortex chamber so that the water will enter the siphon chamber and set up eddies or a whirling motion. in the water therein. Opposite to the said nozzle 9 and extending in an inclined downward direction therefrom is a nozzle-shaped outlet 5 (hereinafter called for distinction nozzle 8) having its larger lower end connected by a pipe t to the ejector nozzle (1 and through which semi-coarse material can flow ,from the bottom of the siphon chamber 1' which is inclined, into nozzle d. The siphon chamber has extending downward from its upper end an external conduit 14 provided with a controlling valve 0 and delivering into a trough w leading to a settling chamber. Arranged in any convenient position isa feed hopper as into which the raw material to be treated is deliyered and from which the raw material is delivered by a down-take pipe 3 into the ejector nozzles. The down-take pipe y is 4 connected through a three-way junction piece and a branch pipe 1, to the nozzle 8, the junction piece being provided with a hand. operated valve 2Twhereby the ejector nozzle d can be placed in communication, at

will, with the feed hopper a: or with the nozzle ,9, or with both nozzle Is' and. feed hopper :0 simultaneously. The feed hopper a2 maybe provided near its lower end with a horizontal sieve 3 of suitable mesh.

The annular vortex channel may be contracted in cross sectional area as at the point 4 where the water with raw material enters it, thereby inducing a circulation of water and solidmaterial in the vortex chamber.

1', and below the outlet of the overflow 'cham. ber m, is a float chamber 5 the lower end of V whichis connectedto the bent/pipe connecting the outlet Q from the'vortex c annel to the'siphon chamber 7'. Within the float chamber 5 is'a float 6 connected to a rod 7, adapted, by the rise and fall of the float, either to operate an electric switch '8 con-' trolling an electro-magnetic device 9 for closingand' opening the valve 10 in the water v gravitate Arranged adjacent to the siphon chamber supply pipe 0, or to mechanically operate such valve. i

Arranged below and communicating with the collecting chamber 71. for coarse material is a second receptacle l1 (hereinafter called the sand receptacle) from which the coarse material is finally discharged. The coarse material carried by centrifugal force and gravity'into the collecting receptacle 71- is. prevented from descending immediately into 7 the sand receptacle 11 below by a small auxiliary stream of water derived from the pipe 0 by piping 12, which is caused to flow upwards through the small outlet i at the bottom of the collecting chamber. This'stream keeps. the coarse particles, collected above the small outlet, in 'a constant state of agitation so long as it continues, washing outany fine particles remaining with the coarse ones. The accumulated coarse particles also serve S as a sand seal effectually to prevent any fine particles suspended in the water above, from being carried into the sand receptacle 11 below. As the auxiliary stream is controlled by the same valve 10 that controls the ejector nozzles d, e, the upward flow of this stream also *ceasessimultaneously with the cessation of the circulation in the vortex chamber, whereupon coarse material is allowed to into the sand receptacle 11.

To discharge the coarse material from the sand receptacle and to prevent a large quan- 1 tity of the water in the apparatusflowing out at the same time, the said sand receptacle 11 may be made of inverted conical shape and of small cross sectional area, and be provided at its lower extremity with an outlet valve 13 through which the coarse material can be allowed to flow. A considerable quantity of coarse material may be allowed to accumulate above the valve be-- fore opening-it, thus forming a sand seal. The valve 13 {hereinafter called for distinction the sand valve) should be closed before sufiicient coarse material has run out to break the seal. It may be operated 'automatically and the sand seal maintainedwithin the desired limits, by any convenient means. For this purpose, the sand valve 13 may be operated by an electro-magnctic device 14, the circuit of which is controlled by an electric switch as shown more particularly in Fig. '2 comprising, for example two switch levers 15, 16 which may be mounted to rotate about'a common center 17. One arm of the lever15-isconnected mechanically to amovable par tfof the means used for controlling the mainwater va'lve say by a rod 18 to the lever controlling valve 10, in such a manner that the lever will be par- 125 tially rotated in a forward and backward 1 direction. each time the main water valve 10 is opened and-closed. The second arm of the said lever 15 carries an insulated con-- tact 19 and also a lateral supporting lug.

The second lever 16 comprises two arms one of which is arranged normally to rest upon the lug 20 on the second arm of the first lever 15 and carries an insulated contact 21 and g'the second arm of the lever 1.6, whiclf may be inclined upward, is weighted as at 22 or otherwise loaded. The lever 16 is connected toa spindle which spindle constitutes the, common-center 17 referred to and is carried 10 into theupper portion of the sand receptacle 11 where it is provided with a vane 23 which moves freely when surrounded only by. water but becomes anchored or fixed by the coarse material as soon as this accumulates in the 15 said receptacle 11 to a sufiicient height-to surround the vane 23. The arrangement is such that the levers 15, 16 can rotate tog'ether andkeep thefswitch'contacts 19, 21 which are associated with the circuit of the electro-magnetic device 14, apart so long-as thevane 23 is free to move but as soon as the second lever 16 is anchored by the coarse material, the first lever l5 rotates relatively thereto with the result that an electric cir 25 cuit is closed through the electro-magnetic device '14 andthe sand valve 13 opened, the valve being closed by a spring or weight or otherwise, as soon as the sand falls below the vane and the switch levers are thus rendered free to assume their original rela tive positions and open the said electric circuit. The sand valve 13 will thus be opened each time the main water valve 10 is operated,'so long as the vane 23 remains an- 85 chored, but ceases to be opened .as soon as f the sand has fallen sufliciently torelease the .vane.

The coarse material discharged from the sand receptacl 11 may be-carried to a mill 4 by any suitable conveyor for further grinding. Where, however, 'the coarse material. or sand is required-to be as free as possiblefrom water before being conveyed to "the mill, the bulk of the small quantity of water flowing out with the sand may be drained off by allowing the sand valveto discharge on to a. belt conveyor in which a pocket is formed between the end rollers of the conveyor by depressing-the belt 24 immediately below or adjacent to the sand discharge, it

may be by means of a. spherically shaped -roller,25 as shown in Fig. 3 or by the weight of the discharged material, the adjacent end roller'being suitably arranged for the purpose. The sand will then be found to clin to the surface'of the'belt and be carried awa by it, whereas-the water will remain in e ketand'eventually, asit accumulates, fi over the sides of the belt. 69 The arrangement issuch that whilst water is being delivered into the vortex-chamber A a, b a suction actipn will be set up in the feed hopper w and water will flow from the vortex. c amber with coarse material into i 55 the collecting chamber it from whichiwater intermittent opening and closing of will rise into and overflow from the overflow chamber m into the float chamber 5 until the float rises to a predetermined height whemit will cause the water supply valve 10 to close, thereby outtingaoff the :0- supply of water and raw material to the vortex .chamber. The water in the overflow chamber m; and in the float chamber 5 will ,then fall, passing partly into' and" through the siphon chamber 1' and partly into the feed hopper at until it'reaches a predetermined lower level in the overflow and float chambers, thereby causing the re-opening of the water valve 10, whereupon the above described operations will be repeated. In this way. a pulsatipg or ebb and flow action will be set up in parts of the apparatus but not in the siphon chamber 1" through which water with fine'material will continu-- ously flow when the apparatus is inuse. By adjusting the high-and lowlimits of movement fof the float.6, the periodicity of ebb and flow can be varied to any desired extent. By-reason of the ebb and How, permanent lodgment of semi-coarse materlal in parts of the apparatus will be avoided and in the caseof thefeed hopper, it will aid in keep in the sieve 3 therein, when used, clean. hat I claim is 1. Means of the kind herein referred to comprisin a feed hopper for material to be grade ,.a vortex. chamber having two delivery outlets, a water supply pipe, a valve in said pipe,fejector means adapted to simu'lta'neouslysupply material from the hopper and Water from the pipe to said vortex chamber, a coarse material collecting chamber in communication with one of said vortex chamber outlets an overflow chamber connected to the'coarse material collecting chamber, afloat chamber, in communication with the vortex chamber, arranged to receive the overflow from the overflow chamber, a float inthe latter and means op- I eratively associated with the water valve 110 and .float whereby movement of the latter due to varying level of water therein causes such,

valve.

2. Means according to claim 1 in which the overflow chamber is adjustablgin height, substantially as described 3. Means of vthe kind herein referred to, comprisinga feed hop er for material to be graded, a vortex c amber having an inlet and an outlet, a siphon chamberin communication with the vortex chamber through such outlet, means connecting the siphon chamber rto the vortex chamber inlet, e'ector'means communicating with both the eedhopper and siphon chamber and with the vortex chamber inlet, a source at water under pressure for operating said ejector means and controlling means whereby the ejector means, feed hopper and siphon 0 chamber can be operatively associated in dif-, ferent relationships.

4. In combination, a feed hopper, a V0?- tex chamber having an inlet and two outlets, an overflow chamber 'connected to one of said outlets, a siphon chamber connected to the second of said outlets, a float chamber adapted to receive liquid from the overflow chamber, ejector means connected to the feed hopper, siphon chamber and Vortexchamber inlet, .a source of Water under presa sure leading to the ejector means, anda float in the floatchamber adapted to intermittentl y establish and interrupt the water supp1y,the arrangement being such that a LEONARD ANDREWS.

15 pulsating action is set up in parts of the f 

